Switch control system



Jan. 7, 1941. M ALL N SWITCH CONTROL SYSTEM Filed Feb. 10, 1939 TOR [e912 INV Earl fir H15 ATTORNEY Patented Jan. 7, 1941 parish STATES PATENT OFFMZE SWITCH CONTROL SYSTEM Earl M. Allen, Swissvale, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania My invention relates to switch control systems, and particularly to improved means for preventing storage of switch control.

It has heretofore been proposed to employ a polarized relay having both neutral and. polar contacts to control the motor, either electric or pneumatic, for operating a railway track switch to effect movement of the switch between a normal and a. reverse position. It has also been proposed heretofore to provide a control circuit for energizing the polarized relay with current of one or the other relative polarity to thereby operate the relay to control the switch motor, while looking relays or route relays have been provided to interrupt the control circuit and thus prevent the control relay from producing a change in the position of the Switch when it is not safe to effect such a change.

If the polarity of the current supplied to the control circuit is changed at a time when the lock relay interrupts the control circuit, no change will be made in the condition of the polarized relay, and therefore, no change will be made in the position occupied by the switch as long as the lock relay remains deenergized.

However, unless some means is provided to prevent such an occurrence, on subsequent energization of the lock relay and picking up of its contacts with resultant completion of the control circuit, the polarized relay will cause the motor to move the switch to the position corresponding to that occupied by the control lever or other mechanism controlling the polarity of the current supplied to the control circuit.

This storage of switch control or delayed movement of the switch may be objectionable and it is desired to provide a switch control system in which storage of switch control is pre vented.

It is an object of my invention to provide an improved switch control system in which storage of switch control is prevented.

A further object of my invention is to provide an improved switch control system which is arranged so that on a change in the position of the control lever, unless the switch control relay promptly responds to such movement of the control lever, no change can be. effected in the condition of the switch control relay until the control lever is first brought to a position: of correspondence with the polar contactsof the relay.

Another object of my invention is to provide an improved switch control system in which no change may be effected in the position of the switch as long as routeor locking relays associated with the switch are deenergized, and in which no change will occur in the position occupied by the switch on picking up of the contacts of the route or looking relays ifthe position of the switch control lever has been changed while the locking relays were released.

Another object of my invention is to provide an improved switch control system employing a polarized switch control relay of the retained neutral type, the control system incorporating means controlled by a neutral contact of that relay for controlling energization of the switch control relay in such manner that under usual operating conditions a change in the direction of energization of the polarized relay must take place within the release time of the neutral contacts of the relay or it cannot take place at all.

Another object of my invention is to provide an improved switch control system incorporating a polarized switch control relay and an auxiliary polarized relay together with means controlled by polar contacts of both polar relays for energizing the switch control relay.

A further object of my invention is to provide an improved switch control system employing a polarized switch control relay to control the circuit for energizing the switch motor, the relay having both polar and neutral contacts and the system being arranged so that when the switch is reversed while in transit, the neutral contacts of the polarized relay must become released before the positions of the polar contacts of the relay can be changed to thereby insure that under these conditions the circuit of the switch motor will be interrupted by the neutral contacts of the relay and not by the polar contacts thereof.

Another object of my inventon an improved switch control system.

Other objects of my invention and features of novelty will be apparent from the following description taken in connection with the accompanying drawing.

I shall describe one form of apparatus embodying my invention, and shall then point out the novel features thereof in claims.

In the drawing the single figure is a diagram illustrating one embodiment of the improved switch control system provided by my invention.

Referring to the drawing, the reference character W designates a railway track switch which is movable between a normal and a reverse position by means of an electric motor M. A polarized switch control relay WR is provided to control the motor M. The system includes, in addiis to provide tion, an auxiliary polarized relay CR, a lock relay LR, and a polarized switch repeating or switch indication relay WRP which cooperate in the manner hereinafter explained to control energization of the switch control relay WR from the control wires 10 and II.

This system also includes a control lever L which may be located at a point remote from the switch. The lever L is movable between a normal position and a reverse position to effect the supply of current of one or the other relative polarity to the control wires I0 and II.

The lever L has associated therewith contacts I4 and i5 which are movable in accordance with movement of the lever L. The contact I4 is constantly connected to terminal B of battery I6, while contact I5 is constantly connected to terminal C of battery I6.

When the lever L is in the normal position, as shown, contact I4 engages a stationary contact to which is connected control wire Ill, while contact I5 engages a stationary contact to which is connected. control wire II so that current of one relative polarity, which may be considered normal polarity, is supplied from battery I6 to the control wires I0 and II.

Similarly, when the control lever L is in the reverse position, contact I4 engages a stationary contact to which is connected the control wire I I, while contact I5 engages a stationary contact to which is connected a branch of control Wire I 3 so that current of the opposite or reverse relative polarity is supplied from battery It to the control wires Ill and II.

The switch W has associated therewith contacts I1, I8, I9, and 26 which are movable in accordance with movement of the switch W to control the switch repeating relay WRP, and to also control the circuit of the switch motor M.

Control wire I0 is connected to one terminal of the winding of switch control relay WR, while a branch of wire W is connected to one terminal of the winding of the auxiilary polarized control relay CR. The control wire I I is connected to front contact 22 of lock relay LR, while a branch of control wire II is connected to a terminal of the winding of relay CR.

The lock relay LR has a movable contact 24 which when. picked up engages contact 22, while contact 24 is connected by wire 26 to neutral contact 21 of switch control relay WR, and also to polar contact 28 of control relay CR. The other terminal of the winding of relay WR is connected by wire 33 to a polar contact 3| of relay WR, and to neutral contact 33 of switch repeating relay WRP.

Contact 28 of auxiliary relay CR, when in the normal position as shown, engages a stationary contact 35 which is connected by wire 36 to contact 31 which is engaged by polar contact (SI of relay WR when that contact is in. its normal position as shown.

Contact 28 of relay CR, when in its reverse position, engages a stationary contact 40 which is connected by wire 4! to contact 43 which is engaged by polar contact 3I of relay WR when that contact is in its reverse position.

Contact 21 of relay WR when picked up engages a contact 45 which is connected by wire 46 to a contact 41, while contact 41 is engaged by contact 33 of relay WRP when contact 33 is picked up.

Contact 21 of relay WR when released engages a stationary contact 48 which is connected by wire 50 to a contact 5I, while contact 5| is engaged by movable contact 33 of relay WRP when contact 33 is released.

It will be seen that when the positions of the polar contacts of the relays WR and CR are in agreement and the contact of the lock relay LR is picked up, a circuit is established to energize the winding of the switch control relay WR from the control wires I0 and I I.

Thus when the polar contacts of both relays CR and WE are in their normal positions, as shown, and contact 24 of relay LR is picked up, a circuit is established from control wire I I to one terminal of the winding of relay WR. This circuit is traced from wire II through contacts 22-24 of lock relay LR, wire 26, contacts 28-35 of relay CR, wire 36, contacts 31-3I of relay WR and wire 30 to one terminal of the winding of relay WR, the other terminal of which has control wire I0 connected thereto.

Similarly, when the polar contacts of both relays CR and WE. are in their reverse positions and contact 24 of relay LR is picked up, a circuit is established from wire II to one terminal of the winding of relay WR. This circuit is traced from wire II through contacts 22-24 of relay LR, wire 26, contacts 28-40 of relay CR, wire 41, contacts 43-3I of relay WR, and wire 30 to one terminal of the winding of relay WR, the other terminal of which has control wire I0 connected thereto.

A circuit is also established to energize the winding of relay WR from the control wires I0 and II when the neutral contacts of both relays WR and WRP are picked up or released.

Thus when contact 21 of relay WR and contact 33 of relay WRP are both picked up, assuming the contact 24 of lock relay LR is also picked up, a circuit is established from control wire II to one terminal of the winding of relay WR. This circuit is traced from Wire II through contacts 22-24 of relay LR, wire 26, contacts 21-45 of relay W'R, wire 46, contacts 41-33 of relay WRP, and wire 30 to one terminal of the winding of relay WR, while the other terminal of the relay winding has control wire I0 connected thereto.

Similarly, when contact 21 of relay WR and contact 33 of relay WRP are both released, a circuit is established to energize the winding of relay WR from the control wires 10 and II providing contact 24 of lock relay LR is picked up. This circuit is traced from wire I I through contacts 22-24 of relay LR, wire 26, contacts 21-48 of relay WR, wire 50, contacts 5I-33 of relay WRP, wire 30, winding of relay WR, and control wire Ill.

The polar contact of relay WR and the switch operated contacts I1, I8, and I9 cooperate to control the supply of current to the polarized. switch repeating relay WRP from a battery 56.

Polar contact 55 of relay WR is connected by wire 58 to one terminal of the winding of relay WRP, while the other terminal or? the winding of relay WRP is connected by wire 59 to switch operated contact I1. Contact 55 when in the normal position, as shown, engages a contact 60 which is connected by wire 62 to switch operated contact I8, while contact 55 when in the reverse position engages polar contact 63 which is connected by wire 64 to switch operated contact I9.

Switch operated contact I1 engages a stationary contact 65 when and only when the switch W is in the normal position, while contact I1 engages a stationary contact 61 when and only 1 when the switch W is in the reverse position. Contact 65 is connected by wire 69to terminal C of battery 56, while contact 61 is connected by wire to terminal B of battery 56.

Switch operated contact I8 engages a stationary contact 12 when and only when the switch V! is in the normal position, while contact 12 has connected thereto a branch. of wire 10 leading from terminal B of battery 56.

Similarly switch operated contact I9engages a stationary contact 13 when and only when the switch W is in the reverse position, while contact 13 has connected thereto a branch of wire 69 leading from terminal C of battery 56.

Although the switch operated contacts I1, I8, and I9 have been described as engaging the stationary contacts associated therewith when the switch is in its normal or its reverse position, it is contemplated that these contacts may be arranged to engage when and only when the switch is in its normal or reverse position and is locked in that position.

The neutral and polar contacts of relay WR and switch operated contact 2|] cooperate to control the energizing circuits of the switch motor M. The neutral contacts 15 of relay WR, when picked up, engage stationary contacts 16 to which are connected a branch of wire 15 leading from terminal B of battery 56. Neutral contacts 15 are connected by wire 11 to normal polar contact 18 and reverse polar contact 19.

Relay WR has a polar contact 80 which is connected by wire ill to one brush of the motor armature 62, While the relay has another polar contact 84 which is connected by wire 85 to the other brush or the motor armature.

Polar contact 86, when in the normal position, as shown, engages a contact 81 which is connected by wire 88 to contact 96 associated with switch operated contact 20, while contact 86 when in the reverse position engages con tact 19.

Contact 84, when in the normal position, as shown, engages contact 18, while When it is in the reverse position, it engages a contact 9| which is connected by Wire 92 to contact 94 associated with the switch operated contact 2!].

Switch operated contact 2|] is connected by wire 55 to one terminal of the motor field winding 56, the other terminal of which is connected to terminal C of battery 56. Contact 20 engages contact 94 in all positions of the switch W excent the reverse position thereof, while contact engages contact 9|] in all positions of the switch W except the normal position thereof.

The relay VVR, is of the retained neutral polar type, that is, on reversal in the direction of energization of the relay winding the neutral contacts of the relay will remain picked up while :the polar contacts change from one position to the other.

The polarized auxiliary control relay CE is designed so that-on a change in the direction of energization of the relay winding the polar 1 contacts of this relay will shift from one position to the other much more rapidly than the polar contacts of relay WR change their positions.

The neutral contact 53 of the polarized switch repeating relay WRP is slow in releasing so that when the contact is picked up, it will remain picked up for a time interval after interruption of the circuit of the relay winding.

The polarized switch repeating relay WRP has .fiin addition to the neutral contact 33 a neutral contact I66 and a polar contact lIlI which are connected by a Wire I02. Contact I00 when picked up engages contact I63 to which is connected wire IIM. Contact IOI when in the normal position, as shown, engages contact I66 to which is connected wire I01, while when contact IOI is in the reverse position, it engages contact I69 to which is connected wire III]. The circuits established by the wires I54, I61 and I III may be employed in any manner Well-known in the art to indicate the position occupied by the switch W.

The winding of the lock relay LR is energized by current supplied over a circuit controlled by trafiic conditions in the vicinity of the switch W in the manner well-knownin the art so that the winding of relay LR is energized only when it is safe to effect the change in the position of the switch W, while the relay LR is deenergized at all other times.

The equipment is shown in the drawing in the position which it assumes when the control lever L and the switch W are in their reverse positions, and when the lock relay LR is energized.

As the control lever L is in the normal position, current of normal relative polarity is supplied from battery I5 to control wires It) and II and the windings of relays CR and WE are energized with the result that the polar contacts of these relays are in their normal positions, as shown, while the neutral contacts of relay WE are picked up.

The winding of relay CR is energized directly from the control wires Ill and I I, while the circuit for energizing the winding of relay WR is traced from wire II through contacts 22-24 of relay LR, wire 26, contacts 28-35 of relay CR, wire 56, contacts 31-3I of relay WR, wire 35, winding of relay WR, and control wire I6.

As the polar contacts of relay WE are in their normal positions and as the switch W is also in the normal position, a circuit is established to energize the switch repeating relay WR with current of normal relative polarity.

This circuit is traced from terminal B of battery 56 through wire 15, contact 12, switch oper ated contact I6, wire 62, contacts 60-55 of relay WR, wire 55, winding of relay WRP, wire 59, switch operated contact I1, contact 65, and wire 69 to terminal C of battery 56.

As the winding of relay WRP is energized, contact 33 is picked up, and as contact 21 of relay WR is picked up at this time, a circuit is established by contacts 21 and 33 to connect control wire I I to a terminal of the winding of relay WR. This circuit is traced from wire I I through contacts 22-24 of relay LR, wire 26, contacts 21-45 of relay WR, wire 45, contacts 41-33 of relay WRP, and wire 35 to a terminal of the winding of relay WR.

At this time the neutral and polar contacts of the relay WR establish a circuit for the switch motor M to cause the motor to move the switch. W to the normal position, but as the switch W is in the normal position contact 26 is out of engagement with the contact 55 with the result that the switch motor circuit is interrupted.

If at this time the operator wishes to effect movement of the switch W from the normal to the reverse position, he may do so by moving the lever L from its normal to its reverse position,.

thereby effecting the supply of current of reverse relative polarity from battery I 5 to the control Wires I6 and II.

On the supply of current of reverse relative polarity to the control wires H] and II polar contact 28 of auxiliary control relay CR is promptly shifted from its normal to its reverse position. On this movement of contact 28 one circuit for energizing the winding of the control relay WR from the control wires l and II is interrupted by movement of contact 28 out of engagement with contact 35. However, at this time the winding of relay WR continues to be energized from control wires I0 and II by means of the circuit established by contact 21 of relay WR and contact 33 of relay WRP.

In addition, upon the supply of current of reverse relative polarity to the control wires l0 and II the polar contacts of the relay WE are shifted from their normal to their reverse positions, but, as previously explained, since the relay CR is much faster operating than the relay WR, the contacts of relay WR do not complete their movement until after contact 28 of relay CR has completed its movement.

Because of the retained neutral characteristic of the relay WR, on reversal of the direction of energization of the winding of the relay with consequent change in the position of the polar contacts of the relay, the neutral contacts 2'! and 15 or" the relay remain picked up, and the contact 21 maintains the circuit for energizing the winding of relay WR from the control wires l9 and H until the polar contacts of relay WR and relay CR have both completed their movement from the normal to the reverse position.

When contact 28 of relay CR and contact 3| of relay WR have both moved to the reverse position, the circuit controlled by these contacts for energizing the winding of relay WR from control wires l0 and II is again complete with the result that the winding of relay WR continues to be energized from the control wires l0 and II after contact 33 of relay WRP becomes released, which occurs on movement of polar contact 55 of relay WR away from the normal position. Be- ;cause of the slow releasing characteristic of the neutral contacts of relay WRP, contact 33 willremain picked up for long enough after movement of contact 55 out of engagement with contact 68 to insure that the polar contacts of relay WR will complete their movement so that contact 3| will reestablish the circuit of the relay winding.

On movement of the polar contacts 80 and 84 of relay WR from their normal to their reverse positions the normal supply circuit for the motor M is interrupted and the reverse supply circuit for the switch motor is established.

The reverse supply circuit for the motor M is traced from terminal B of battery 56 through .wire 10, contacts l6'|5 of relay WR, wire 17, reverse polar contacts 19-89 of relay WR, wire 8|, motor armature 82, wire 85, reverse polar contacts 849| of relay WR, wire 92, contact 94, switch operated contact 20, wire 95, motor field winding 96, and terminal 0 of battery 56.

On movement of the switch W away from the normal position contacts I1 and I8 are moved out of engagement with contacts 65 and 12, respectively, while when the switch W is moved to the reverse position, contact 20 is moved out of engagement with contact 94 to thereby interrupt the reverse supply circuit for the switch motor M. In addition, on movement of the switch W to the reverse position contact I! is moved into engagement with contact 61, while contact |9 is moved into engagement with contact 13 to thereby establish a circuit for energizing the winding of relay WRP. This circuit is traced from terminal B of battery 56 through wire 10, contact 61, switch operated contact I1, wire 59, winding of relay WRP, wire 58, reverse polar contacts 5563 of relay WR, wire 64, switch operated contact l9, contact 13, and wire 69 to terminal C of battery 76.

On energization of the winding of relay WRP contact 33 of the relay is again picked up to reestablish the circuit controlled thereby. However, at this time the winding of the relay WR is energized from the control wires 9 and II over the circuit which includes polar contact 28 of relay CR and polar contact 3| of relay WR so that picking up of contact 33 of relay WRP has no significance.

In a similar manner, if while the switch W is in the reverse position the operator desires to effect movement of the switch to the normal position, he may do so by moving the lever L from the reverse to the normal position, thereby again effecting the supply of current of normal relative polarity to the control wires l8 and I.

On the supply of current of normal relative polarity to the control wires l0 and II the polar contact 28 of relay CR is shifted from the reverse to the normal position, and on this movement of the contact 28 the circuit controlled thereby for energizing the winding of relay WR from the control wires I8 and I is interrupted.

However, at this time contact 2! of relay WR and contact 33 of relay WRP remain picked up and maintain the circuit which they control for energizing the winding of relay WR from the control wires l0 and II. Accordingly, the winding of relay WR is energized with current of normal relative polarity with the result that the polar contacts of relay WR are shifted from the reverse to their normal positions, and on movement of contact 3| of relay WR to the normal position the circuit controlled by contact 3| and contact 28 of relay CR is again complete so that the winding of relay WR continues to be energized from control wires l0 and H after contact 33 of relay WRP becomes released.

On movement of the polar contacts of relay WR from their reverse to their normal positions contact 55 is shifted out of engagement with contact 63, thereby interrupting the circuit for energizing the winding of relay WRP. Because of the slow releasing characteristic of contact 33 of relay WRP this contact does not release instantaneously, but remains picked up until after the polar contacts of the relay WR have completed their movement so that contact 3| completes the circuit for energizing the winding of relay WR from the control wires l0 and II before contact 33 of relay WRP becomes released.

In addition, upon movement of the polar contacts of relay WR from their reverse to their normal positions the reverse supply circuit of the switch motor M is interrupted and the normal supply circuit for the motor is established to cause the motor to move the switch from the reverse to the normal position.

The normal supply circuit is traced from terminal B of battery 56 through wire 19, contacts l6-l5 of relay WR, wire 17, normal polar con tacts 'l884 of relay WR, wire 85, motor armature 82, wire 8|, normal polar contacts 88-8! of relay WR, Wire 88, contact 90, switch operated contact 20, wire 95, motor field winding 96, and terminal C of battery 56.

When the switch W completes its movement to the normal position, contact 28 is moved out of engagement with contact 90, thereby interrupting the normal supply circuit for the switch motor M. with the result that the motor no longer is energized.

In addition, on completion of movement of the switch W to the normal position switch operated contact I8 is moved into engagement with contact l2, while switch operated contact I! is moved into engagement with contact 65 to thereby establish the circuit for energizing the winding of relay WRP. This circuit is traced from terminal 33 of battery 5t through wire 10, contact l2, switch operated contact 18, wire 52, normal polar contacts 6055 of relay WE, wire 58, winding of relay WRP, wire 59, switch operated contact ll, contact 65, wire 59 to terminal C of battery 56.

On energization of the winding of relay WRP contact 33 of the relay again becomes picked up, but as the winding of relay WR is energized at this time by current supplied from the control. wires Ill and H over the circuit established by polar contact 28 of relay CR. and polar contact 3| of relay WR, picking up of contact 33 is with out result.

From the foregoing it will be seen that under normal conditions on a. change in the polarity of the current supplied to the control wires IE3 and Il a circuit controlled by the polar contacts of relays CR and WR for energizing the winding of the relay WR from the control wires [8 and ii is momentarily interrupted during movement oi these contacts from one position to the other. However, at this time a circuit for energizing the winding of relay WR from the control wires it! and ii is temporarily maintained by the circuit controlled by neutral conte. ct 21 of relay WB. and neutral contact 33 of relay VVRP so that the winding of relay WR is continuously ener gized from the control wires I!) and H during movement of the polar contacts of relays CR and WR.

When the polar contacts of relays CR and WR complete their movement, they reestablish the circuit controlled thereby for energizing the winding of the relay WR from the control wires it and H so that the winding of relay WR remains energized after contact 33 of relay WRP becomes released.

Under normal operating conditions, therefore. on a change in the polarity of the current supplied to the control wires Ill and H the winding of relay WR remains continuously connected to the control wires ill and l l and the polar contacts of the relay WE are shifted from one position to the other to complete the normal or reverse supply circuit for the switch motor M.

The system provided by my invention is arranged so that if the polarity of the current supplied to the control wires Hi and ii is changed at a time when the switch W is in transit between one of its positions and the other, the polar contacts of the relay WR will remain in-the position which they occupy, while the neutral contacts of the relay become released and thus interrupt the circuit of the switch motor. Thereafter the polar contacts of relay WE will shift from one position to the other and subsequently the neutral contacts of the relay will become picked up to reestablish the motor circuit.

This sequence of operation of the contacts of the relay WE at this time is desirable as it insures that the circuit of the switch motor will be interrupted by the neutral contacts, which are adapted for this service, and not by the polar contacts of the relay, which are not adapted for such service.

For purposes of illustration it will be assumed that the switch W is being moved from the normal to the reverse position and that before the switch attains the reverse position the operator decides to return the switch to the normal position.

In order to effect movement of the switch W to the reverse position the operator moves the control lever L from the normal to the reverse position, thereby effecting the supply of current of reverse relative polarity to the control wires it and Ill. At this time the relays CR and WR operate as previously described in detail and the polar contacts of the relay VVR establish the reverse supply circuit for the motor M to cause the motor M to move the switch W towards the reverse position, while contact 28 of relay CR and contact 3! of relay WR cooperate to establish the circuit for energizing the winding of relay WE from the control wires Ill and H.

In addition, polar contact 55 of relay WR interrupts the circuit of the winding of relay WRP so that contact 33 of this relay becomes released and engages its back point of contact. The circuit of the winding of relay WRP is additionally interrupted by switch operated contacts I! and ill on movement of the switch W away from the normal position.

When the operator decides to return the switch W to the normal position, he returns the control lever L to the normal position, thereby again effecting the supply of current of normal relative polarity to the control wires Ill and II. On the supply of current of this polarity to control wires in and I! contact 28 of relay GR is shifted from its reverse to its normal position. As previously explained, contact 28 of relay CR operates very quickly with the result that it is moved out of engagement with contact 40 to thereby interrupt the circuit of the winding of relay WR before the winding of relay WR has been energized sufiiciently with current of normal relative polarity to effect movement of polar contact ill from its reverse to its normal position. Accordingly, contact 3| and the other polar contacts of relay WR remain in their reverse positions and the reverse supply circuit for the motor is not interrupted by the polar contacts of relay WR.

On movement of contact 28 of relay CR to the normal position at a time when polar contact 3| of relay WR is in the reverse position the circuit controlled by these contacts for energizing the winding of relay WR from control wires l and I l is interrupted.

Furthermore, at this time as contact 33 ofrelay WRP is released, while neutral contact 21 of relay WR is momentarily held picked up, no circuit is established by these contacts to energize the winding of relay WR from the control wires It! and II. The winding of relay WE, therefore, is deenergized.

After a short time interval the neutral contacts of relay WR become released and contacts T interrupt the reverse supply circuit for the motor M while contact 21 engages contact 43. At this time, as contact 33 of relay WRP is in engagement with contact 5|, a circuitis established to energize the winding of relay WR from control wires ill and II, this circuit being traced from wire l1 through contacts 2224 of relay LR, wire 26, contacts 2lfl3 of relay WR, Wire fill, contacts 5l33 of relay WRP, and wire 30 to one terminal of the winding of relay VVR, while the other terminal of this winding is connected to control wire Ill.

Accordingly, on release of contact 21 of relay WR the winding of the relay WR becomes energized with current of normal relative polarity supplied from the control wires l and II. The operating characteristics of relay WR are such that on energization of its winding the polar contacts of the relay will shift from their reverse to their normal positions before the winding of the relay has been energized to a degree sufiicient to eiTect picking up of the neutral contacts of the relay. Accordingly, the polar contacts of the relay WR will be shifted from their normal to their reverse positions as a result of energization of the winding of relay WR by current supplied over back contact 48 of the relay. The normal supply circuit for the switch motor M is not complete on this movement of the polar contacts of relay WR since the neutral contacts 15 of the relay remain released.

When the polar contact 3| of relay WR is shifted from the reverse to the normal position, it is again in agreement with the position occupied by the polar contact 28 of relay CR and the circuit controlled by the polar contact 28 of relay CR and the polar contact 3| of relay WR for energizing the winding of relay WR from control wires Ill and H is again complete.

The neutral contacts 2'! and 15 of the relay WR now become picked up. On picking up of contact 21 and movement of this contact out of engagement with contact 48 to interrupt the circuit controlled by contact 21 for energizing the winding of relay WR, the winding of relay WR does not become deenergized, but continues to be energized by current supplied over the circuit controlled by polar contact 28 of relay CR and polar contact 3| of relay WR.

On picking up of the neutral contacts 15 of the relay WR at a time when the polar contacts of the relay are in their normal positions, the normal supply circuit for the switch motor M is again complete and this motor is operated to return the switch W to the normal position. When the switch attains the normal position, the contact 20 is moved out of engagement with contact 90 to interrupt the normal supply circuit for the switch motor M, while contacts I! and I8 establish the circuit for energizing the winding of relay WRP.

The system operates in a similar manner if while the switch W is being moved towards the normal position the operator decides to return the switch W to the reverse position.

When the switch W is in transit, the contact 33 of relay WRP is released and interrupts the circuit controlled by this contact and by contact 21 of relay WR for energizing the winding of relay WR during movement of the polar contacts of relays CR and WR from one position to the other.

On the supply of current of reverse relative polarity to the control wires I0 and II at a time when the switch W is being moved to the normal position, contact 28 of relay CR is promptly shifted to the reverse position, thereby interrupting the circuit for energizing the winding of relay WR from the control wires l0 and II. Accordingly, the neutral contacts of relay WR become released and interrupt the normal supply circuit for the switch motor M, while contact 21, when released, cooperates with contact 33 of relay WRP to establish a circuit for energizing the winding of relay WR from the control wires l0 and II.

As current of reverse relative polarity is supplied to the control wires l0 and II at this time, the polar contacts of relay WR will be shifted to their reverse position and contact 3| will be in correspondence with contact 28 of relay CR, and these contacts will establish a circuit for energizing the winding of relay WR from the control wires I 0 and II. Subsequently the neutral contacts of relay WR become picked up and complete the reverse supply circuit for the motor M.

The system provided by my invention is arranged so that when the contact 24 of the lock relay LR is released, the circuit for energizing the winding of the relay WR is interrupted and cannot be completed as long as contact 24 remains released. As the winding of relay WR is deenergized when the contact of the lock relay LR is released, the neutral contacts 15 of relay WR are released and interrupt the circuit of the switch motor M with the result that the motor M is deenergized and cannot be energized as long as the contact 24 of the lock relay LR remains released.

Thus it will be seen that when the contact of the lock relay LR is released, no connection is established from control wire H to wire 26, and hence even if a circuit is established by polar contact 28 of relay CR and polar contact 3| of relay WR, or by neutral contact 21 of relay WR and neutral contact 33 of relay WRP, from wire 36 to wire 30 leading to a terminal of the winding of relay WR, the winding of relay WR will not be energized and the neutral contacts of this relay will remain released.

If while the contact 24 of lock relay LR is released the control lever L is moved from one position to the other, thereby efiecting a change in the polarity of the current supplied to the control wires l0 and II, the relay WR will not be affected since, as explained above, the connection from the control wire II to the relay winding is interrupted at this time.

The system provided by my invention is also arranged so that if the position of the control lever L is changed while the contact 24 of the lock relay LR is released, no change will take place in the condition of the relay WR on subsequent picking up of the lock relay contact at a time when the control lever and the polar contacts of the relay VVR are out of correspondence.

It will be seen that the winding of the auxiliary control relay CR is energized from the control wires ill and H by a circuit independent of the lock relay LR so that the contact 28 of the relay CR responds to changes in the polarity of the current supplied to the control wires I0 and I I both when the lock relay LR is deenergized and when it is energized.

For purposes of illustration, it will be assumed that the contact of the lock relay becomes released at a time when the control lever L and the switch W are in their normal positions, and that while the lock relay LR is deenergized, the control lever L is shifted to the reverse position.

On release of the contacts of the lock relay LR at a time when the winding of relay WR is energized with current of normal relative polarity, the winding of relay WR is deenergized, as explained above, and the neutral contacts 2'! and 15 of the relay become released, while the polar contacts of the relay remain in their normal positions.

At this time as the switch W is in the normal position, the switch operated contacts It! and i8 establish a circuit to energize the winding of relay WHIP with the result that contact 33 of relay WRP is picked up. As contact 33 of relay WRP is picked up, and as contact 21 of relay WR- is released, these contacts do not establish a circuit to connect control Wire 26 to wire 130.

On movement of the control lever L to the reverse position and resultant supply of current of reverse relative polarity to the control wires ill and ill the polar contact 28 of relay GR is shifted from the normal to the reverse position, thereby interrupting the circuit controlled jointly by this contact and by polar contact 3| of relay WR for establishing connection from wire it to wire 30,

It will be seen that at this time both circuits for establishing connection from wire 25 to wire 3'] are interrupted. Accordingly, on subsequent picking up of the contact 24 of lock relay LB with resultant completion of the circuit from control wire l l to wire 26 the winding of relay WR does not become energized since no connection is established from wire 25 to wire 30 leading to one terminal of thewinding of relay WR.

The winding of relay WR, therefore, remains deenergized and the neutral contacts of the relay remain released, while the polar contacts of relay WR remain in their normal positions. As the neutral contacts of relay WE are released, the circuit of the switch motor M is interrupted and the switch W will remain in the normal position.

The operator may regain control of the switch W by returning the control lever L to the normal position, that is, to a position in correspondence with the polar contacts of relay WR.

On movement of control lever L to the normal position current of normal relative polarity is again supplied to the control wires Iii and Il with the result that contact 28 of relay CE is shifted from the reverse tov the normal position.

On movement of contact 28 to the normal position at a time when polar contact SI of relay WR is also in the normal position the circuit controlled by these contacts for establishing connection from wire to wire 30 is again complete. As the circuit from wire 26 to wire 33 is now complete, and as it is assumed that the contact 24 of lock relay LR is picked. up, the circuit for energizing the winding of relay WR from the control wires 1!) and II is complete and this winding is energized with current of normal relative polarity.

On energization of the winding of relay WR with current of normal relative polarity the neutral contacts of the relay become picked. up, while the polar contacts of the relay remain in their normal positions. On picking up of neutral contact ill of relay WR the circuit controlled by this contact and by neutral contact 33 of relay WRP for energizing the Winding of relay WR is again complete.

If the operator now desires to effect movement of the switch ,W to the reverse position, he may do so by moving the control lever L from the normal to the reverse position, thereby effecting the supply of current of reverse relative polarity to the control wires H! and l I, while the equipment will operate in the manner previously described in detail and the motor M will drive the switch W to the reverse position.

The system operates in substantially the same manner if while the control lever L and the switch Ware in their reverse positions the contact of .the lock relay LR. becomes released, and if while the lock relay contact 24 is released the control lever L is shifted to the normal position. Under such circumstances, no change will take place in the condition of the relay WR on subsequent picking up of the contact of the lock relay LR.

lhe operator, however, may regain control of the switch W by returning the control lever L to the reverse position, that is, to the position corresponding to the position occupied by the polar contacts of relay WE.

Although I have herein shown and described only one form of switch control system embodying my invention, it is understood that various changes. and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In a switch control system, in combination, a railway track switch movable between a normal and a reverse position, a motor for moving said switch, a polarized switch control relay operative when its winding is energized with current of one relative polarity to condition the m0- tor to move the switch to its normal position, said relay being operative when its winding is energized with current of the opposite relative polarity to condition the motor to move the switch to its reverse position, said relay having a neutral contact which is picked up when the relay winding is energized with current of either polarity and which when picked up remains picked up for a time interval subsequent to interruption of the circuit of the relay winding, an indication relay having a slow releasing neutral contact, means operable when and only when the switch is in either its normal or its reverse position for energizing the winding of the indication relay, a pair of control wires, means for selectively supplying to said control wires current of one or the other relative polarity, a circult controlled 'by the neutral contact of the switch control relay and by the neutral contact of the indication relay for energizing the winding of the switch control relay from said control wires, a circuit controlled by a polar contact of the switch control relay for also energizing the winding of the switch control relay from said control wires, and a lock relay governed by traffic conditions in the vicinity of the switch and controlling the circuit of the switch control relay windin 2. In a switch control system, in combination, a railway track switch movable between a normal and a reverse position, a motor for moving said switch, a polarized switch control relay operative when its winding is energized with current of one relative polarity to condition the motor to move the switch to its normal position, said relay being operative when its winding is energized with current of the opposite relative polarity to condition the motor to move the switch to its reverse position, said relay having a neutral contact which is picked up when the relay winding is energized with current of either polarity and which when picked up remains picked up for a time interval subsequent to interruption of the circuit of the relay Winding, an indication relay having a slow releasing neutral contact, means operable when and only when the switch is in either its normal or its reverse position for energizing the winding of the indication relay, a pair of control wires, means for selectively supplying to said control wires current of one or the other relative polarity, a circuit controlled by the neutral contact of the switch control relay and by the neutral contact of the indication relay for energizing the winding of the switch control relay from said control wires, an auxiliary polarized relay having a winding constantly energized from said control wires, a circuit controlled jointly by a polar contact of said auxiliary relay and by a polar contact of the switch control relay for also energizing the winding of the switch control relay from said control wires, and a lock relay governed by traflic conditions in the vicinity of the switch and controlling the circuit of the switch control relay winding.

3. In a switch control system, in combination, a railway track switch movable between a normal and a reverse position, a motor for moving said switch, a polarized switch control relay operative when its winding is energized with current of one relative polarity to condition the motor to move the switch to its normal position, said relay being operative when its winding is energized with current of the opposite relative polarity to condition the motor to move the switch to its reverse position, said relay having a neutral contact which is picked up when the relay winding is energized with current of either polarity and which when picked up remains picked up for a time interval subsequent to interruption of the circuit of the relay winding, an indication relay having a slow releasing neutral contact, means operable when and only when the switch is in either its normal or its reverse position for energizing the winding of the indication relay, a pair of control wires, means for selectively supplying to said control wires current of one or the other relative polarity, a circuit controlled by the neutral contact of the switch control relay and by the neutral contact of the indication relay for energizing the winding of the switch control relay from said control wires, said circuit being complete when and only when both of said contacts are released or when both of said contacts are picked up, a circuit controlled by a polar contact of the switch control relay for I also energizing the winding of the switch control relay from said control wires, and a lock relay governed by traflic conditions in the vicinity of the switch and controlling the circuit of the switch control relay winding.

4. In a switch control system, in combination, a railway track switch movable between a normal and a reverse position, a motor for moving said switch, a. polarized switch control relay operative when its winding is energized with current of one relative polarity to condition the motor to move the switch to its normal position, said relay being operative when its winding is energized with current of the opposite relative polarity to condition the motor to move the switch to its reverse position, said relay having a neutral contact which is picked up when the relay winding is energized with current of either polarity and which when picked up remains picked up for a time interval subsequent to interruption of the circuit of the relay winding, an indication relay having a slow releasing neutral contact, means operable when and only when the switch is in either its normal or its reverse position for energizing the winding of the indication relay, a pair of control wires, means 'for selectively supplying to said control wires current of one or the other relative polarity, a circuit controlled by the neutral contact of the switch control relay and by the neutral contact of the indication relay for energizing the winding of the switch control relay from said control wires, an auxiliary polarized relay having a winding constantly energized from said control wires, a circuit controlled jointly by a polar contact of said auxiliary relay and by a polar contact of the switch control relay for also energizing the winding of the switch control relay from saidcontrol wires, said circuit being complete when and only when the polar contacts of both relays are in their normal positions or when the polar contacts of both relays are in their reverse positions, and a lock relay governed by trafiic conditions in the vicinity of the switch and controlling the circuit of the switch control relay winding.

5. In a switch control system, in combination, a railway track switch movable between a normal and a reverse position, a motor for moving said switch, a polarized switch control relay operative when its winding is energized with current of one relative polarity to condition the motor to move the switch to its normal position, said relay being operative when its winding is energized with current of the opposite relative polarity to condition the motor to move the switch to its reverse position, said relay having a neutral contact which is picked up when the relay winding is energized with current of either polarity and which when picked up remains picked up for a time interval subsequent to interruption of the circuit of the relay winding, an indication relay having a slow releasing neutral contact, means operable when and only when the switch is in either its normal or its reverse position for energizing the winding of the indication relay, a pair of control wires, means for selectively supplying to said control wires current of one or the other relative polarity, a circuit controlled by the neutral contact of the switch control relay and by the neutral contact of the indication relay for energizing the winding of the switch control relay from said control wires, said circuit being complete when and only when both of said contacts are released or when both of said contacts are picked up, an auxiliary polarized relay having a winding constantly energized from said control wires, a circuit controlled jointly by a polar contact of said auxiliary relay and by a polar contact of the switch control relay for also energizing the winding of the switch control relay from said control wires, said circuit being complete when and only 7 contacts being picked up when the relay winding is energized with current of either polarity and when picked up remaining picked up for a time interval subsequent to interruption of the circuit of the relay winding, a neutral contact of said relay controlling the supply circuit for energizing said motor, said neutral contact when picked up establishing said supply circuit and when released interrupting said supply circuit, the

polar contacts of said relay being operative when the relay winding is energized with current of one relative polarity to energize the motor from said supply circuit so as to cause the motor to move the switch to one position, the polar contacts of said relay being operative when the relay winding is energized with current of the opposite relative polarity to energize the motor from said supply circuit so as to cause the motor to move the switch to its other position, an indication relay having a slow releasing neutral contact, means operable when and only when the switch is in either its normal or its reverse position for energizing the winding of said indication relay, a pair of control wires, means for selectively supplying to said control wires current of one or the other relative polarity, and a circuit controlled by a neutral contact of the switch control relay and by the neutral contact of the indication relay for energizing the winding of the switch control relay from said control wires.

7. In a switch control system, in combination, a railway track switch movable between a normal and a reverse position, an electric motor for operating said switch, a polarized switch control relay having neutral and polar contacts, the neutral contacts being picked up when the relay winding is energized with current of either polarity and when picked up remaining picked up for a time interval subsequent to interruption of the circuit of the relay winding, a neutral contact of said relay controlling the supply circuit for energizing said motor, said neutral contact when picked up establishing said supply circuit and when released interrupting said supply circuit, the polar contacts of said relay being operative when the relay winding is energized with current of one relative polarity to energize the motor from said supply circuit so as to cause the motor to move the switch to one position, the polar contacts of said relay being operative when the relay Winding is energized with current of the opposite relative polarity to energize the motor from said supply circuit so as to cause the motor to move the switch to its other position, an indication relay having a slow releasing neutral contact, means operable when and only when the switch is in either its normal or its reverse position for energizing the winding of said indication relay, a pair of control wires, means for selectively supplying to said control wires current of one or the other relative polarity, a circuit controlled by a neutral contact of the switch control relay and by the neutral contact of the indication relay for energizing the winding of the switch control relay from said control wires, an auxiliary polarized relay having its winding constantly connected to said control wires, and a circuit controlled by a polar contact of said auxiliary relay and by a polar contact of said switch control relay for also energizing the winding of the switch control relay from said control wires.

8. In a switch control system, in combination a railway track switch movable between a normal and a reverse position, an electric motor for operating said switch, a polarized switch control relay having neutral and polar contacts, the neutral contacts being picked up when the relay winding is energized with current of either polarity and when picked up remaining picked up for a time interval subsequent to interruption of the circuit of the relay winding, a neutral contact of said relay controlling the supply circuit for energizing said motor, said neutral contact when picked up establishing said supply circuit and when released interrupting said supply circuit, the polar contacts of said relay being operative when the relay winding is energized with current of one relative polarity to energize the motor from said supply circuit so as to cause the motor to move the switch to one position, the polar contacts of said relay being operative when the relay winding is energized with current of the opposite rela tive polarity to energize the motor from said supply circuit so as to cause the motor to move the switch to its other position, an indication relay having a slow releasing neutral contact, means operable when and only when the switch is in either its normal or its reverse position for energizing the winding of said indication relay, a pair of control wires, means for selectively supplying to said control wires current of one or the other relative polarity, a circuit controlled by a neutral contact of the switch control relay and by the neutral contact of the indication relay for energizing the winding of the switch control relay from said control wires, an auxiliary polarized relay having its winding constantly connected to said control wires, a circuit controlled by a polar contact of said auxiliary relay and by a polar contact of said switch control relay for also energizing the winding of the switch control relay from said control wires, and a lock relay governed by trafiic conditions in the vicinity of the switch and controlling the circuit of the winding of the switch control relay.

9. In a switch control system, in combination, a railway track switch movable between 2. normal and a reverse position, a motor for moving said switch, a polarized switch control relay having polar contacts which when the relay winding is energized with current of normal relative polarity are moved to their normal position and condition the motor to move the switch to the normal position and when the relay winding is energized with current of reverse relative polarity said polar contacts being moved to their reverse position to condition the motor to move the switch to its reverse position, said relay having a neutral contact which is picked up when the relay winding is energized with current of either polarity and which when picked up remains picked up for a time interval subsequent to interruption of the circuit of the relay winding, an indication relay having a slow releasing neutral contact, means operable when and only when the switch is in either its normal or its reverse position for energizing the winding of the indication relay, a pair of control wires, means for selectively supplying to said control wires current of one or the other relative polarity, a circuit controlled by a neutral contact of the switch control relay and by the neutral contact of the indication relay for energizing the winding of the switch control relay from said control wires, a circuit controlled by a polar contact of said switch control relay for also energizing the winding of said switch control relay from said control wires, means operative when said polar contact is in its normal position to permit flow or current of normal polarity only in the circuit controlled by said polar contact, and means operative when said polar contact is in its reverse position to permit flow of current of reverse polarity only in the circuit controlled by said polar contact.

10. In a switch control system, in combination, a railway track switch movable between a normal and a reverse position, a motor for moving said switch, a polarized switch control relay having polar contacts which when the relay winding is energized with current of normal relative polarity are moved to their normal position and condition the motor to move the switch to the normal position and when the relay winding is energized with current of reverse relative polarity said polar contacts being moved to their reverse position to condition the motor to move the switch to its reverse position, said relay having a neutral contact which is picked up when the relay winding is energized with current of either polarity and which when picked up remains picked up for a time interval subsequent to interruption of the circuit of the relay winding, an indication relay having a slow releasing neutral contact, means operable when and only when the switch is in either its normal or its reverse position for energizing the winding of the indication relay, a pair of control wires, means for selectively supplying to said control wires current of one or the other relative polarity, a cir cult controlled by a neutral contact of the switch control relay and by a neutral contact of the indication relay for energizing the winding of the switch control relay from said control wires, a circuit controlled by a polar contact of said switch control relay for also energizing the winding of said switch control relay from said control wires, means operative when said polar contact is in its normal position to permit flow of current of normal polarity only in the circuit controlled by said polar contact, means operative when said polar contact is in its reverse position to permit flow of current of reverse polarity only in the circuit controlled by said polar contact, and a lock relay govern-ed by traffic conditions in the vicinity of the switch and controlling the circuit of the switch control relay.

11. In a switch control system, in combination, a railway track switch movable between a normal and a reverse position, a motor for moving said switch, a polarized switch control relay having polar contacts which when the relay winding is energized with current of normal relative polarity are moved to their normal position and condition the motor to move the switch to the normal position and when the relay winding is energized with current of reverse relative polarity said polar contacts being moved to their reverse position to condition the motor to move the switch to its reverse position, said relay having a neutral contact which is picked up when the relay winding is energized with current of either polarity and which when picked up remains picked up for a time interval subsequent to interruption of the circuit of the relay winding, an indication relay having a slow releasing neutral contact, means operable when and only when the switch is in either its normal or its reverse position for energizing the winding of the indication relay, a pair of control wires, means for selectively supplying to said control wires current of one or the other relative polarity, a circuit controlled by a neutral contact of the switch control relay and by the neutral contact of the indication relay for energizing the winding of the switch control relay from said control wires, said circuit being complete when and only when both of said contacts are released or when both of said contacts are picked up, a circuit controlled by a polar contact of said switch control relay for also energizing the winding of said switch control relay from said control wires, means operative when said polar contact is in its normal position to permit fiow of current of normal polarity only in the circuit controlled by said polar contact, and means operative when said polar contact is in its reverse position to permit flow of current of reverse polarity only in the circuit controlled by said polar contact.

12. In a switch control system, in combination, a railway track switch movable between a normal and a reverse position, a motor for moving said switch, a polarized switch control relay having polar contacts which when the relay winding is energized with current of normal relative polarity which when picked up remains picked up for a time interval subsequent to interruption of the circuit of the relay winding, an indication relay having a slow releasing neutral contact, means operable when and only when the switch is in either its normal or its reverse position for energizing the winding of the indication relay, a pair of control wires, means for selectively supplying to said control wires current of one or the other relative polarity, a circuit controlled by a neutral contact of the switch control relay and by the neutral contact of the indication relay for energizing the winding of the switch control relay from said control wires, said circuit being complete when and only when both of said contacts are released or when both of said contacts are picked up, a circuit controlled by a polar contact of said switch control relay for also energizing the winding of said switch control relay from said control wires, means operative when said polar contact is in its normal position to permit flow of current of normal polarity only in the circuit controlled by said polar contact, means operative when said polar contact is in its reverse position to permit flow of current of reverse polarity only in the circuit controlled by said polar contact, and a lock relay governed by trailic conditions in the vicinity of the switch and controlling the circuit of the switch control relay.

13. In a switch control system, in combination, a railway track switch movable between a normal and a reverse position, an electric motor for operating said switch, a polarized switch control relay having neutral and polar contacts controlling circuits for energizing said motor, the neutral contacts being picked up when the relay winding is energized with current of either polarity and when picked up remaining picked up for a time interval subsequent to interruption of the circuit of the relay winding, a neutral contact of said relay controlling the supply circuit for energizing said motor, said neutral contact when picked up establishing said supply circuit and when released interrupting said supply circuit, the polar contacts of said relay being operative when the relay Winding is energized with current of one relative polarity to energize the motor from said supply circuit so as to cause the motor to move the switch to one position, the polar contacts of said relay being operative when the relay winding is energized with current of the opposite relative polarity to energize the motor from said supply circuit so as to cause the motor to move the switch to the other position, an indication relay having a slow releasing neutral contact,

ill

means operable when and only when the switch is in either its normal or its reverse position for energizing the winding of said indication relay, a pair of control wires, means for selectively supplying to said control wires current of one or the other relative polarity, a. circuit controlled by a neutral contact of the switch control relay and by the neutral contact of the indication relay for energizing the winding of the switch control relay from said control wires, a circuit controlled by a polar contact of said switch control relay for also energizing the winding of said switch control relay from said control wires, means operative when said polar contact is in its normal position to permit flow of current of normal relative polarity only in the circuit controlled by said polar contact, and means operative when said polar contact is in its reverse position to permit flow of current of reverse polarity only in the circuit controlled by said polar contact.

14. In a switch control system, in combination, a railway track switch movable between a normal and a reverse position, an electric motor for operating said switch, a polarized switch control relay having neutral and polar contacts controlling circuits for energizing said motor, the neutral contacts being picked up when the relay winding is energized with current of either polarity and when picked up remaining picked up for a time interval subsequent to interruption of the circuit of the relay winding, a neutral contact of said relay controlling the supply circuit for energizing said motor, said neutral contact when picked up establishing said supply circuit and when released interrupting said supply circuit, the polar contacts of said relay being operative when the relay winding is energized with current of one relative polarity to energize the motor from said supply circuit so as to cause the motor to move the switch to one position, the polar contacts of said relay being operative when the relay winding is energized with current of the opposite relative polarity to energize the motor from said supply circuit so as to cause the motor to move the switch to the other position, an indication relay having a slow releasing neutral contact, means operable when and only when the switch is in either its normal or its reverse position for energizing the winding of said indication relay, a pair of control wires, means for selectively supplying to said control wires current of one or the other relative polarity, a circuit controlled by a neutral contact of the switch control relay and by the neutral contact of the indication relay for energizing the winding of the switch control relay from said control wires, said circuit being complete when and only when both of said neutral contacts are picked up or when both of said neutral contacts are released, a circuit controlled by a polar contact of said switch control relay for also energizing the winding of said switch control relay from said control wires, means operative when said polar contact is in its normal position to permit flow of current of normal relative polarity only in the circuit controlled by said polar contact, and means operative when said polar contact is in its reverse position to permit flow of current of reverse polarity only in the circuit controlled by said polar contact.

15. In a switch control system, in combination, a railway track switch movable between a normal and a reverse position, a motor for moving said switch, a retained neutral polarized relay having neutral and polar contacts controlling said motor, a pair of control conductors, means for selectively supplying to said control conductors current of one or the other relative polarity, a circuit controlled by a polar contact of said relay for energizing the relay winding from said con- 5 trol conductors, means operative when said polar contact is in one position to permit flow of current of one relative polarity only in the circuit controlled :by said polar contact, means operative when said polar contact is in its other position to permitflow of current of the other relative polarity only in the circuit controlled by said polar contact, and a circuit controlled by a neutral contact of said relay and by means governed in accordance with the position of the switch for also energizing said relay winding from said control conductors, said circuit being complete when said neutral contact is picked up provided the switch is in either its normal or its reverse position, said circuit also being complete when said neutral contact is released provided the switch is not in either its normal or its reverse position.

16. In a switch control system, in combination, a railway track switch movable between a normal and a reverse position, a motor for moving 1'25 said switch, a retained neutral polarized relay having neutral and polar contacts controlling said motor, a pair of control conductors, means for selectively supplying to said control conductors current of one or the other relative polarity, a circuit controlled by a polar contact of said relay for energizing the relay winding from said control conductors, means operative when said polar contact is in, one position to permit flow of current of one relative polarity only in the cir- 453, cuit controlled by said polar contact, means operative when said polar contact is in its other position to permit fiow of current of the other relative polarity only in the circuit controlled by said polar contact, a circuit controlled by a new 40 tral contact of said relay and by means governed in accordance with the position, of the switch for also energizing said relay winding from said control conductors, said circuit being complete when said neutral contact is picked up provided the switch is in either its normal or its reverse position, said circuit also being complete when said neutral contact is released provided the switch is not in either its normal or its reverse position, and a lock relay governed by traffic conditions in the vicinity of the switch and controlling the circuit of said relay winding.

17. In a switch control system, in combination, a railway track switch movable between a normal and a reverse position, a motor for moving said switch, a retained neutral polarized relay having neutral and polar contacts controlling said motor to cause the motor to move the switch to one or the other of its positions, the relay polar contacts being moved to their normal position when the relay winding is energized with current of normal relative polarity and being moved to their reverse position when the relay winding is energized with current of reverse relative polarity, a pair of control conductors, means for selectively supplying to said control conductors current of one or the other relative polarity, a circuit controlled by a polar contact of said relay for energizing the relay winding from said control conductors, means operative when said polar contact is in its normal position to permit flow of current of normal relative polarity only in the circuit controlled by said polar contact, means operative when said polar contact is in its reverse position to permit flow of current of reverse relative po- 75 larity only in the circuit controlled by said polar contact, and a circuit controlled by a neutral contact of said relay and by means governed in accordance with the position of the switch for also energizing said relay winding from said control conductors, said circuit being complete when said neutral contact is picked up provided the switch is in either its normal or its reverse position, said circuit also being complete when said neutral contact is released provided the switch is not in either its normal or its reverse position.

18. In a switch control system, in combination, a railway track switch movable between a normal and a reverse position, a motor for moving said switch, a retained neutral polarized relay having neutral and polar contacts controlling said motor to cause the motor to move the switch to one or the other of its positions, the relay polar contacts being moved to their normal position when the relay winding is energized with current of normal relative polarity and being moved to their reverse position when the relay winding is energized with current of reverse relative polarity, a pair of control conductors, means for selectively supplying to said control conductors current of one or the other relative polarity, a circuit controlled by a polar cont-act of said relay for energizing the relay winding from said control conductors, means operative when said polar contact is in its normal position to permit flow of current of normal relative polarity only in the circuit controlled by said polar contact, means operative when said polar contact is in its reverse position to permit flow of current of reverse relative polarity only in the circuit controlled by said polar contact, a circuit controlled by a neutral contact of said relay and by means governed in accordance with the position of the switch for also energizing said relay winding from said control conductors, said circuit being complete when said neutral contact is picked up provided the switch is in either its normal or its reverse position, said circuit also being complete when said neutral contact is released provided the switch is is not in either its normal or its reverse position, and a lock relay governed by trafiic conditions in the vicinity of the switch and controlling the circuit of said relay winding.

19. In a switch control system in combination,

a railway track switch movable between a normal and a reverse position, a motor for moving said switch, a polarized relay having neutral and polar contacts controlling circuits for controlling said motor to eiTect movement of said switch between its two positions, a pair of control wires, a source of current, means for selectively supplying from said source to said control wires current of one or the other relative polarity, a first circuit controlled by a polar contact of said relay for energizing said relay winding from said control wires, means operative when said relay polar contact is in its normal position to permit flow of current of normal polarity only in said first circuit, means operative when said relay polar contact is in its reverse position to permit flow of current of reverse polarity only in said first circuit, a lock relay governed by trafiic conditions in the vicinity of said switch, and a second circuit controlled by said lock relay and through which current of either relative polarity may be supplied from said control wires to the winding of said polarized relay.

20. In a switch control system, in combination, a railway track switch movable between a normal and a reverse position, a motor for moving said switch, a retained neutral polarized relay having neutral and polar contacts controlling circuits for controlling said motor to effect movement of said switch between its two positions, a pair of control wires, means for selectively supplying to said control wires current of one or the other relative polarity, a first circuit controlled by a polar contact of said relay for energizing said relay winding from said control wires, means operative when said relay polar con-tact is in its normal position to permit fiow of current of normal polarity only in said first circuit, means operative when said relay polar contact is in its reverse position to permit flow of current of reverse polarity only in said first circuit, a second circuit for energizing said relay winding from said control wires, said second circuit including a neutral contact of said relay and being complete only when said neutral contact is in its picked up position, and a lock relay governed by traffic conditions in the vicinity of said switch and controlling said second circuit.

EARL M. ALLEN. 

